Sunshine during Nighttime Darkness

Even the lighting conditions are considerably altered in space.
As is generally known, the concept of day is associated with the
notion of a blue sky or sunlit clouds and scattering of light
in all directions, without direct sunlight being necessary. All
of these phenomena are, however, due only to the presence of the
Earth's atmosphere, because in it a part of the incident radiation
of the sun is refracted, reflected and scattered in all directions
many times; one of the results of this process is the impression
of a blue color in the sky. The atmosphere produces a widespread
and pleasant, gradual transition between the harshness of sunlight
and darkness.

This is all impossible in empty space because air is absent there.
As a result, even the concept of day is no longer valid, strictly
speaking. Without letup, the sky appears as the darkest black,
from which the infinite number of stars shine with extreme
brightness
and with a constant untwinkling light, and from which the sun
radiates, overwhelming everything with an unimaginably blinding
force.

And yet as soon as we turn our gaze from it, we have the impression
of night, even though our back is being flooded by sunlight
because,
while the side of the object (e.g., an umbrella) turned towards
the sun is brightly illuminated by its rays, nighttime darkness
exists on the back side. Not really complete darkness! After all,
the stars shine from all sides and even the Earth or Moon, as
a result of their reflectivity, light up the side of the object
in the sun's shadow. But even in this case, we observe only the
harshest, brightest light, never a mild, diffuse light.